Field of the Invention
The invention relates to a plating apparatus configured to plate a to-be-plated body (substrate) such as a semiconductor wafer, a plating apparatus controlling method, and a storage medium configured to store a program for instructing a computer to implement the plating apparatus controlling method.
Description of the Related Art
It has been practiced to form wiring in a microscopic wiring groove, a hole or an opening of a resist, which is provided in or on the surface of a semiconductor wafer or the like, and also form bumps (protruding electrodes) electrically contacting package electrodes in the surface of a semiconductor wafer or the like. Known methods for forming the wiring and the bumps include, for example, an electrolytic plating method, an evaporation method, a printing method, and a ball bump forming method. Along with the increase of I/O terminals on semiconductor chips and the decrease of pitches of the semiconductor chips, the electrolytic plating method is becoming more widely used because of its capability of producing smaller bumps and its relatively stable performance.
In recent years, there have been needs for performing plating processing with respect to substrates warped in various ways by means of plating apparatuses. Meanwhile, it is becoming known that, when the substrates warped in various ways are plated while being held by substrate holders, poor sealing contributes to occurrence of leakage and deteriorates the in-surface uniformity of a plating film.
Japanese Patent No. 5643239 (Patent Document 1) discloses a substrate holder configured to clamp the outer circumferential portion of a substrate by using first and second holding members. The first holding member is formed of a backing base and a movable base that is supported by a compression spring to be movable relative to the backing base. The substrate holder is designed so that, when the substrate is placed on the movable base and clamped between the first and second holding members, the substrate is biased toward the second holding member to absorb thickness change in the substrate, to thereby hold the substrate while maintaining the compression size of a seal member provided to the substrate holder within a definite range.
Japanese Patent No. 5782398 (Patent Document 2) discloses a substrate holder configured to clamp the outer circumferential portion of a substrate by using first and second holding members. When the substrate is held by the substrate holder, a gap between the first and second holding members is sealed with a first seal member of the second holding member, and at the same time, the outer circumferential portion of the substrate is sealed with a second seal member of the second holding member. This creates an internal space in the substrate holder by the first and second holding members and the substrate. The above-described plating method using the substrate holder conducts a first leakage test in which the internal space is vacuumed to see if the internal space reaches a predetermined vacuum pressure after the elapse of a predetermined period of time to check the sealing capabilities of the first and second seal members. The method then conducts a second leakage test that seals the internal space of the substrate holder holding the substrate, which has passed the first leakage test, to see if the pressure in the internal space reaches a predetermined or higher value within a predetermined period of time to further check the sealing capabilities of the first and second seal members. The method then performs the plating processing with respect to substrates by using the substrate holders that have passed the first and second leakage tests.